21155561074 has 32 divisors (see below), whose sum is σ = 34295063040. Its totient is φ = 9764428800.

The previous prime is 21155561057. The next prime is 21155561083. The reversal of 21155561074 is 47016555112.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78354 + ... + 220114.

It is an arithmetic number, because the mean of its divisors is an integer number (1071720720).

Almost surely, 2^21155561074 is an apocalyptic number.

21155561074 is a deficient number, since it is larger than the sum of its proper divisors (13139501966).

21155561074 is a wasteful number, since it uses less digits than its factorization.

21155561074 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141906.

The product of its (nonzero) digits is 42000, while the sum is 37.

The spelling of 21155561074 in words is "twenty-one billion, one hundred fifty-five million, five hundred sixty-one thousand, seventy-four".